C onstantinos Martinos is a Greek shipping magnate and a key figure in one of the world's most powerful shipping dynasties. He is one of three brothers—along with Andreas and Athanasios—who are all billionaires in the maritime industry. The family's business was founded by their mother, Athina Martinos, but the brothers later split the assets to build their own independent shipping empires.

Constantinos leads Thenamaris, one of the world's most prominent and respected independent ship management companies. Thenamaris operates a large and diversified fleet of vessels, including oil tankers, bulk carriers, container ships, and LNG carriers. He is known for his shrewd and often contrarian investment strategy, buying and selling ships at opportune moments in the highly cyclical shipping market. Like the rest of his family, he maintains an extremely low public profile, consistent with the discreet nature of the traditional Greek shipping community.